Field
The present invention generally relates to microfluidic systems, and, more particularly, to optically controlled microfluidic systems.
Prior Art
Digital microfluidics deals with the manipulation of discrete liquid droplets, using manipulation technologies including electrowetting, dielectrophoresis, optical forces, magnetic forces, surface acoustic waves, or thermocapillary forces. However the effectiveness of some of the devices using these technologies has been limited. Some electrowetting devices for example, have fixed electrode configurations and/or fixed droplet volumes. Additionally, some devices are unable to move a droplet in a desired direction on a device surface, and/or have to address wiring of large numbers of electrodes.
Optically controlled digital microfluidic systems, also called optically controlled microfluidic systems or light-actuated digital microfluidic systems, typically use a continuous photoconductive surface enabling the projection of light to create virtual electrodes on the surface. These virtual electrodes can be used to transport, generate, mix, separate droplets, and for large scale multidroplet manipulation. An important advantage of these systems is that they are capable of moving droplets in different directions, able to move droplets of different volumes, reprogrammable, and therefore potentially very versatile in carrying multiple types of chemical reactions. For example, they can be used to create a miniature, versatile, chemical laboratory on a microchip (“lab on a chip”).
However current solutions for controlling droplet movements in optically controlled microfluidic devices use manually programmed droplet movements. It is difficult to specify the motions of droplets manually, particularly when the number of droplets becomes large.
Hence there is a need for methods and systems for fully automated collision-free droplet coordination in optically controlled microfluidic systems.